When experiencing a virtual environment graphically and audibly, a participant is often represented in the virtual environment by a virtual object. A virtual sound source produces sound that varies realistically as movement between the virtual sound source and the virtual object occurs. The person participating in the virtual environment hears sound corresponding to the sound that would be heard by the virtual object representing the person in the virtual environment. In attempting to achieve this goal, one or more signals associated with a simulated signal source may output through one or more stationary output devices.
Sound associated with a simulated sound source in a computer simulation is played through one or more stationary speakers. Because the speakers are stationary relative to the participant in the virtual environment, they do not always accurately reflect a location of the simulated sound source, particularly when there is relative movement between the virtual sound source and the virtual object representing the participant.
Accurate spatial location of the simulated sound source provides a realistic interpretation of a virtual environment, for example. This spatial location (e.g., position) of a simulated sound source is a function of direction, distance, and velocity of the simulated sound source relative to a listener represented by the virtual object. Independent sound signals from sufficiently separated fixed speakers around the listener can provide some coarse spatial location, depending on a listener's location relative to each of the speakers. However, other audio cues or binaural cues (e.g., relating to two ears) can be employed to indicate position and motion of the simulated sound source. For example, one such audio cue may be the result of a difference in the times at which sounds from the speakers arrive at a listener's left and right ears, which provides an indication of the direction of the sound source relative to the listener. This characteristic is sometimes referred to as an inter-aural time difference (ITD). Another audio cue relates to the relative amplitudes of sound reaching the listener from different sources.
There is no universally acceptable approach to guarantee accurate spatial localization with fixed speakers, even with using high-cost, complex calculations. Nevertheless, it would be beneficial to devise an alternative that provides more accurate spatial localization.